1. Field of the Invention
The present invention relates to head suspension assemblies for use in data storage disk drives, and in particular to low profile head suspension assemblies having load and unload capability, increased vibration damping and improved attachment of head lead wires.
2. Description of the Related Art
As data storage disk drives continue to be reduced in size, the drives are subject to much higher mechanical shock loads than before. Small form factor drives in portable applications, for example are especially subject to damage from being dropped. One of the more difficult types of damage to eliminate is damage to the head and/or data storage disk caused by impact of the head against the disk, often referred to as head/disk slap.
Because a disk drive is more likely to experience a high mechanical shock load when it is not in operation, one conventional method of nearly eliminating head/disk slap damage is to park the head off the disk when the disk drive is not in use. This is conventionally done by the use of a load and unload ramp that a load and unload tang of a head suspension assembly slides along, thereby moving the head between a position on the disk and a position parked off the disk.
One of the major disadvantages of using a conventional load and unload ramp and tang approach is the necessity of making the head suspension assembly by hand. This disadvantage occurs because conventional head suspension assemblies that include a load and unload tang are small and complex in design. Conventionally, the load and unload tang is built into a load beam, i.e., the beam which is used to hold and position the head in close proximity to the disk. Typical examples of this conventional arrangement are described in U.S. Pat. Nos. 5,027,241 and 5,187,625. In such conventional arrangements, the load and unload tang is an obstacle during fabrication of the head suspension assembly, particularly when routing head lead wires over the load beam and bonding the wires to bonding pads on a slider carrying the head. People must do this complex wire routing and bonding by hand, and automation is ruled out.
Also, the head lead wires connected to the slider resist the necessary pitch and roll movement of the slider. Movement of the slider in the pitch and/or roll direction is necessary for the slider to remain at a substantially constant fly height above the surface of the disk. The slider must be free to respond to very minute deviations from a perfect plane as the disk rotates at high speed so that the head can read and write reliably the data on the disk and so that the slider is prevented from impacting the surface of the rotating disk and thus destroying some of the disk surface and any data stored therein. As the air bearing surface features of the slider are reduced in size, the deleterious effect of the wires on the pitch and roll movement of the slider becomes more significant. This restraining influence of the wires on the slider must be minimized, while at the same time the wires must be positioned and restrained so that they resist being pulled from the slider and thus render the head ineffective.
Further, when the head lead wires are connected to the slider by being looped away from the load beam, the wires consume excessive height which defeats efforts to minimize the overall disk drive height.
Still further, as data storage disk drives are reduced in size, the recording density is increased and consequently vibrations of the head suspension assembly tend to become more significant. To insure reliable read/write operations, such vibrations either must be eliminated or must cease prior to any read/write operations. The latter option, however, disadvantageously affects the access speed of the disk drive.
Accommodating all of the foregoing conditions and requirements becomes a significant undertaking when designing the head suspension assembly for a data storage disk drive having load and unload capability.